1. Field of the Invention
This invention relates to a polymer based on a conjugated diene and dienophilic component, to its production and to its use.
2. Discussion of Related Art
Such polymers are known. Thus, Japanese patent JA 93/1121 describes a copolymer produced from a maleic anhydride, a conjugated diene and an aliphatic monoolefin. Butadiene was used as the conjugated diene and isobutene as the aliphatic monoolefin. The polymerization was carried out in the presence of a peroxide at temperatures of around 150xc2x0 C. The molecular weight Mw is in the range from 500 to 50,000.
In Bull. Chem. Soc. Japan 40 (1967), pages 1272 to 1273, Iwamoto and Yuguchi describe alternating copolymers of 2,4-hexadiene and maleic anhydride. The polymerization is initiated by heating and/or by radical-forming initiators. It may be carried out both in bulk and in solution. The yields are of the order of 2 to 97%.
Japanese patent JA 93/295041 also describes a copolymer of a conjugated diene and maleic anhydride. Conjugated dienes are butadiene or isoprene. The catalyst used is an acetyl acetonate with metals of Group VII or Group VIII. The polymer is used for coating, for surface treatment, for sealing and as an adhesive.
These known polymers have the following disadvantages:
On the one hand, both monomers are based on petrochemicals and thus lead to a more negative ecological assessment by comparison with the use of monomers based on renewable raw materials. On the other hand, the range of raw materials for petrochemical conjugated dienes is limited to butadiene and simple derivatives or homologs thereof. The use of these short-chain dienes represents not only a process-related disadvantage on account of the volatility and ready inflammability of these monomers. From the chemical perspective, too, these compounds only allow minor variations in the chemical properties of the polymers. For example, no reactions with functionalized dienes are possible or indeed described.
Reaction products of maleic anhydride with fatty acids containing conjugated double bonds are also known. However, the reactions involved here are additions based on the Diels-Alder Reaction. This reaction is described, for example, by Behr and Handwerk in Sci. Technol. 94 (1992), pages 206 to 208.
The problem addressed by the present invention was to provide new high-performance polymers based on renewable raw materials by an economic method.
The solution provided by the invention is defined in the claims and lies essentially in a polymer obtainable from:
A) at least one fatty acid with a conjugated Cxe2x80x94C double bond or derivatives thereof,
B) at least one alkene or alkine component containing electron acceptor substituents and optionally
C) at least one copolymerizable alkene component with no electron acceptor substituents.
Component A
The xe2x80x9cfatty acid containing a conjugated Cxe2x80x94C double bondxe2x80x9d (component A) is an aliphatic unsaturated carboxylic acid containing 6 to 32 and, more particularly, 16 to 24 carbon atoms which has two or more conjugated Cxe2x80x94C double bonds. This so-called conjuene fatty acid may be used in functionalized form as an ester or amide for the polymerization reaction.
One preferred embodiment of the invention is characterized by the use of esters or partial esters of the conjuene fatty acids with monohydric or polyhydric alcohols. xe2x80x9cAlcoholsxe2x80x9d are understood to be hydroxyl derivatives of aliphatic or alicyclic, saturated or unsaturated, linear or branched hydrocarbons. Both monohydric and dihydric alcohols or higher alcohols may be used. Specific examples from the low molecular weight range include methanol, ethanol, propanol, butanol, pentanol, decanol, octadecanol, 2-ethylhexanol, 2-octanol, ethylene glycol, propylene glycol, trimethylene glycol, tetramethylene glycol, 2,3-butylene glycol, hexamethylenediol, octamethylenediol, neopentyl glycol, 1,4-bis-hydroxymethyl cyclohexane, Guerbet alcohol, 2-methylpropane-1,3-diol, hexane-1,2,6-triol, glycerol, trimethylol propane, trimethylol ethane, penta-erythritol, sorbitol, formitol, methyl glycoside, butylene glycol, reduced dimer and trimer fatty acids and higher polyethylene, polypropylene and polybutylene glycols. Alcohols derived from colophony resins, such as abietyl alcohol, may also be used for the esterification. OH-containing tertiary amines may also be used.
Other suitable derivatives of the conjuene fatty acids are amides which may be obtained by reaction with ammonia, primary and secondary amines or polyamines, for example with monoethanolamine, stearylamine, diethanolamine, ethylenediamine and hexamethylenediamine.
The xe2x80x9cfatty acid containing a conjugated Cxe2x80x94C double bondxe2x80x9d may be obtained in various ways.
The conjugated double bond may also have been originally present (naturally occurring conjuene fatty acids).
The conjugated double bond may be formed by selective hydrogenation of fatty acids containing conjugated triple bonds (conjuene fatty acids by selective hydrogenation).
The conjugated double bond may also be formed by isomerization of so-called isolene fatty acids either thermally or by the action of catalysts (conjuene fatty acids by isomerization). For example, the isolated double bonds in linoleic, linolenic, arachidonic and clupanodonic acid are converted into conjugated double bonds by the action of catalysts. Specific isomerization catalysts are nickel on supports, transition metals/noble metals, tert.butyl hypochloride, iodine/iodide, sulfur dioxide, selenium/selenium-containing catalysts, metal complexes, alkali metals, treated clays, sulfur-containing catalysts, alkali metal alcoholates and alkali metal hydroxides.
In addition, the conjugated double bond may be formed by dehydration of hydroxyfatty acids either from hydroxy compounds already containing a correspondingly positioned double bond or from dihydroxyfatty acids. The dehydration of hydroxyfatty compounds to conjugated fatty compounds is largely achieved by the addition of acidic catalysts.
Numerous catalysts are described in the literature, for example for the dehydration of castor oil, including for example hetero polyacids (U.S. Pat. No. 2,261,633, 1939), Na2S2O7 (Paint Manuf. 19, 118, 1949), sulfuric acid (U.S. Pat. No. 2,392,119, 1946), phosphorous acid (GB 671,368, 1952), boric acid (U.S. Pat. No. 2,278,425, 1939) and phthalic anhydride (U.S. Pat. No. 224,678), which lead to dehydrated castor oils. The conjugated fatty acids may be obtained from these oils by hydrolysis. However, acetylated hydroxyfatty compounds may be converted into the conjugated fatty acids by thermal ester pyrolysis. Thus, DE-C3-20 18 712, for example, describes the pyrolysis of diacetoxystearic acid methyl ester at 420 to 580xc2x0 C. which is said to give conjuene yields of 80%.
Finally, the conjugated double bonds may be produced by partial or total syntheses.
The polymerization may have to be preceded by stereoisomerization into the E,Z-, Z,E- or Z,Z-configuration.
The following are specific examples of fatty acids containing conjugated double bonds:
naturally occurring conjuene fatty acids, such as sorbic acid, 2,4-decadienoic acid, 2,4-dodecadienoic acid, 10,12-octadecadienoic acid, 9-hydroxy-10,10-octadecadienoic acid, 13-hydroxy-9,11-octadecadienoic acid, 9,14-dihydroxy-10,12-octadecadienoic acid, 9,12,14-octadecatrienoic acid, 8,10,12-octadecatrienoic acid, elaeostearic acid (trichosanoic acid: punicic acid; catalpa acid), licanic acid, camolenic acid, parinaric acid;
conjuene fatty acids by selective hydrogenation, such as isanoic acid, isanolic acid, ximenynic acid, matricaria acid, lachnophyllic acid, mycomycinic acid;
conjuene fatty acids by isomerization of isolene fatty acids, for example Edenor UKD 60/10(Henkel KGaA);
conjuene fatty acids by dehydration of hydroxyfatty acids, such as ricinene fatty acid from ricinoleic acid.
Preferred components A are ricinene fatty acid, ricinene fatty acid methyl ester, UKD fatty acids, UKD fatty acid methyl ester, dehydrated castor oil, conjugated safflower oil and sunflower oil. The UKD fatty acids or fatty acid methyl esters are fatty acids and fatty acid methyl esters with conjugated double bonds which can be obtained from polyunsaturated fatty acids, more especially based on sunflower oil.
Component B1
An xe2x80x9calkene or alkyne component containing electronic acceptor substituentsxe2x80x9d (component B) is understood to be a compound containing 3 to 100 and, more particularly, 4 to 32 carbon atoms which, adjacent the Cxe2x80x94C double or Cxe2x80x94C triple bond, contains at least one electron-attracting substituent, for example one of the following groups: xe2x80x94CN, xe2x80x94COOH, xe2x80x94CHO, xe2x80x94COR, xe2x80x94COOR, xe2x80x94CONH2, xe2x80x94CONHR, xe2x80x94CONR2 or xe2x80x94NO2, where R is an alkyl group containing 1 to 98 carbon atoms.
Specific examples are maleic acid, citric acid, itaconic acid, aconitic acid, acetylene dicarboxylic acid and 3,4,5,6-tetrahydrophthalic acid. However, derivatives of these acids, such as anhydrides, imides, alkylimides containing 1 to 30 carbon atoms in the alkyl group, nitriles, amides, alkyl and arylamides containing 1 to 30 carbon atoms in the alkyl/aryl group, aldehydes, esters and semiesters of alcohols containing 1 to 30 carbon atoms. Examples of such derivatives include maleic anhydride, maleic imide, maleic acid dinitrile, maleic acid dihexyl ester, maleic acid benzyl butyl ester, fumaric acid dihexyl ester, fumaric acid dinitrile, fumaric acid monoethyl ester, itaconic anhydride, itaconic acid dimethyl ester, acetylene dicarboxylic acid diethyl ester and 3,4,5,6-tetrahydrophthalic anhydride. Mixtures of the derivatives mentioned may also be used.
Preferred components B1 are maleic acid, citraconic acid, itaconic acid, aconitic acid, 3,4,5,6-tetrahydrophthalic acid and derivatives thereof.
Component B2
Besides the acids mentioned above, the corresponding derivatives of the following acids may be used as a second component: crotonic acid, cinnamic acid, acrylic acid, methacrylic acid, cyanoacrylic acid and 2,4-pentadienoic acid. These acids may also be used in the form of derivatives, such as amides, alkyl and dialkyl amides containing 1 to 30 carbon atoms in the alkyl group, nitriles, aldehydes, esters and semiesters of alcohols containing 1 to 30 carbon atoms. Examples include, methyl, ethyl, n-propyl, n-butyl, isopropyl, isobutyl, sec.butyl and tert.butyl, n-pentyl, n-hexyl, 2-ethylhexyl, cyclohexyl, n-heptyl, n-octyl, phenylethyl, 2-methoxyethyl, 2-butoxyethyl, phenylpropyl and furfuryl acrylate and methacrylate; also cinnamic acid ethyl ester, crotonic acid amide, methacrylamide, acrylamide, ethyl cyanoacrylate, methyl crotonate, crotonic acid nitrile, cinnamic acid benzyl ester and cinnamic aldehyde.
Component C
An xe2x80x9calkene with no electron acceptor substituentsxe2x80x9d (component C) is, for example, a vinyl ether, vinyl ester, x-olefin, styrene derivative, conjugated hydrocarbon or vinyl pyrrolidone, the alkyl group of the ethers and esters containing 1 to 30 carbon atoms. Examples include vinyl acetate, propionate, butyrate, laurate and stearate, ethyl vinyl ether, 1-decene and xcex1-methyl styrene, xcex2-methyl styrene, vinyl toluene and tert.butyl styrene, chlorostyrene, butadiene and isoprene. Preferred components C are vinyl ether, vinyl ester, styrene and vinyl pyrrolidone.
The molar ratio between components A, B and C is in the range from 1:0.1 to 10:0 to 10 and preferably in the range from 1:0.5 to 1.5:0.2 to 10.
The average molecular weight (weight average Mw) of the polymers according to the invention is above 5,000 and preferably above 10,000. Molecular weights of up to 1,700,000 g/mole were obtained. The molecular weights were determined by gel permeation chromatography (see Examples).
The properties of the polymers according to the invention depend upon the educts and the reaction conditions and range from soft, extremely tacky through rubber-elastic to non-tacky, solid polymers.
Basically, the polymers according to the invention may be prepared simply by mixing the reaction components A and B and optionally C and heating the resulting mixture.
The polymers according to the invention may be prepared both in bulk and in solution or dispersion. Suitable solvents are those which do not have a radical-inhibiting effect. The solvents used are selected, for example, from ethers, such as tetrahydrofuran and dioxane; alcohols, such as methanol, ethanol and isopropanol; esters, such as ethyl acetate, propyl acetate and n-butyl acetate; glycol ether acetates, such as methyl, ethyl and butyl glycol acetate; ketones, such as acetone and cyclohexanone; dialkyl carboxylic acid amides, such as dimethyl formamide, dimethyl acetamide and N-methyl pyrrolidone; aromatic hydrocarbons, such as benzene, toluene and the xylenes; aliphatic hydrocarbons, such as hexane and isooctane; alicyclic hydrocarbons, such as cyclohexane; and chlorinated hydrocarbons, such as methylene chloride, chloroform, dichloroethane and tert.butyl chloride. Other suitable solvents are substances which, by virtue of their low vapor pressure, are normally used as plasticizers, for example fatty acid esters, polyethylene glycols and phthalic acid esters.
However, the polymerization may also be carried out as emulsion polymerization (droplet polymerization).
If no initiators are used, the reaction temperature should be in the range from 20 to 250xc2x0 C. and more particularly in the range from 80 to 200xc2x0 C. Since the reaction is exothermic, it is sufficient to heat the reaction mixture to temperatures of 40 to 150xc2x0 C. If radical-forming initiators are used, temperatures of 0 to 200xc2x0 C. and, more particularly, 30 to 150xc2x0 C. are sufficient as the reaction temperature.
Suitable radical initiators are acetyl cyclohexane sulfonyl peroxide, peroxydicarbonates, diisopropyl peroxydicarbonate, t-amyl perneodecanoate, t-butyl perneodecanoate, t-amyl perpivalate, bis-(2,4-dichlorobenzoyl)-peroxide, t-butyl perpivalate, bis-(3,5,5-trimethylhexanoyl) peroxide, dioctanoyl peroxide, didecanoyl peroxide, dilauroyl peroxide, bis-(2-methylbenzoyl)-peroxide, succinyl peroxide, diacetyl peroxide, dibenzoyl peroxide, t-butyl-per-2-ethyl hexanoate, bis-(4-chlorobenzoyl)-peroxide, t-butyl perisobutyrate, t-butyl permaleate, 1,1-bis-(t-butylperoxy)-3,5,5-trimethyl cyclohexane, 1,1-bis-(t-butylperoxy)-cyclohexane, t-butylperoxyisopropyl carbonate, t-butyl-per-3,5,5-trimethylhexanoate, 2,5-dimethylhexane-2,5-diperbenzoate, t-butyl peracetate, t-amyl perbenzoate, t-butyl perbenzoate, 2,2-bis-(t-butylperoxy)-butane, 2,2-bis-(t-butylperoxy)-propane, dicumyl peroxide, t-butyl cumyl peroxide, 3-t-butylperoxy-3-phenyl phthalide, bis-(t-butylperoxyisopropyl)-benzene, 2,5-dimethylhexane-2,5-di-t-butyl peroxide, 3,5-bis-(t-butylperoxy)-3,5-dimethyl-1,2-dioxalane, di-t-butyl peroxide, 2,5-dimethylhexine-3,2,5-di-t-butyl peroxide, 3,3,6,6,9,9-hexamethyl-1,2,4,5-tetraoxacyclononane, p-menthane hydroperoxide, pinane hydroxide, diisopropylbenzene monohydroperoxide, cumene hydroperoxide, t-butyl hydroperoxide, azo-bis-(2,4-dimethylvaleronitrile), azo-bis-(isobutyronitrile), dibutyl peroxydicarbonate, diisononanoyl peroxide, t-butyl perisononanoate, di-t-butyl peroxide, 1,1-bis-(t-butylperoxy)-3,5,5-trimethyl cyclohexane, 3,5-bis-(t-butylperoxy)-3,5-dimethyl-1,2-dioxolane, 2,5-dimethylhexine-2,5-di-t-butyl peroxide, acetyl cyclohexane sulfonyl peroxide, dicyclohexyl peroxydicarbonate, bis-(4-t-butylcyclohexyl)-peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, dimyristyl peroxydicarbonate, dicetyl peroxydicarbonate, t-butyl perisononanoate, t-butyl perbenzoate, t-butyl perpivalate, t-butyl peroxymaleate, t-butyl peroxybenzoate, dicumyl peroxide, didecanoyl peroxide, methyl ethyl ketone peroxide, 2,2xe2x80x2-azo-bis-(2,2-dimethylvaleronitrile), 2,2xe2x80x2-azo-bis-(2,3-dimethylbutyronitrile) and 2,2xe2x80x2-azo-bis-isobutyronitrile.
These radical initiators are used in quantities of 0.05 to 10% by weight and, more particularly, in quantities of 0.1 to 3% by weight, based on component A.
It has surprisingly been found that, in the case of technical conjuene fatty acids containing saturated and unsaturated fatty acids, such as stearic, oleic and linoleic acid, as secondary components, the polymerization reaction is not inhibited although the unsaturated fatty acids containing isolated double bonds do themselves have inhibitor properties. Accordingly, the reaction product generally contains these very fatty acids or derivatives thereof as an extractable secondary constituent. The crude polymers therefore had soft-elastic properties which can be advantageous for special applications. Plasticizer-free polymers can be obtained by purification, for example by distillation or fractional precipitation.
Where polymerization is carried out in solution, the polymer can precipitate. Should this not be the case, the polymer is precipitated by addition of a solvent with a lower or higher polarity than the reaction medium. In general, the monomeric secondary products remain in solution where working up is carried out in this way and can thus be removed. The polymers can also be fractionated by dissolution and precipitation, for example with acetone/hexane or acetone/water mixtures. The polymers may also be freed from monomers and other low molecular weight substances by distillation.
The polymers thus produced may be directly used for coating, bonding, sealing, filling or as a material.
However, the reactive groups in the polymer may also be completely or partly reacted. Carboxylic acid or derivatives thereof, above all the anhydride group of the polymer according to the invention, are suitable for this purpose.
The polymer-modifying reagents may be monofunctional or polyfunctional.
The functionalities well known from organic chemistry may serve as the functional groups. These include, above all, hydroxy, mercapto, ether, ester, carboxyl, carboxylate, amino and amido groups. Groups reactive to the polymer are, above all, epoxy, isocyanate, mercapto, hydroxy and amino groups. Specific examples of polymer-modifying reagents are
alcohols, such as methanol, ethanol, isopropanol, butanol, long-chain fatty alcohols, unsaturated fatty alcohols, branched fatty alcohols, fatty alcohol ethoxylates, abietol, benzyl alcohol, phenoxyethanol, monoethanolamine, diethanolamine, triethanol amine, ethylene glycol, propylene glycol, polyethylene glycols, polypropylene glycols, hexane-1,6-diol, 1,12-dihydroxyoctadecane, glycerol diacetate, 1,2-O-isopropylidene glycerol, monoacyl glycerides, ricinoleic acid methyl ester, lactic acid ethyl ester, hydroxybutyric acid;
amines, such as butylamine, octadecylamine, benzylamine, ethylenediamine, hexamethylenediamine, Jeffamines, 1,4-phenylenediamine;
epoxides, such as ethylene oxide, propylene oxide, cyclohexene oxide, xcex1-olefin oxides, epoxidized fats and oils, epoxidized fatty acids and alkyl esters thereof, epoxy hardeners, such as bisphenol-A-diglycidyl ether.
The compounds obtained by the polymer-analog reaction may in turn be further reacted, for example by oxidative post-curing in the presence of siccatives, grafting, dehydration to imides and reaction with isocyanates.
Salt formation, vulcanization, post-crosslinking with peroxides and hydrogenation are also mentioned as particular forms of polymer modification. So far as the reaction with salts is concerned, it is important to distinguish between monovalent and polyvalent metals. The polyvalent metals, for example calcium, zinc and aluminium, lead to crosslinked polymers (ionomers), as described in DE 42 11 118. Crosslinked polymers may also be otherwise obtained where polyfunctional reagents are used.
The polymer-analog reaction may be carried out in bulk or in solution. Only solvents which do not react with the functional groups of the polymer are suitable, for example ethers, such as diethyl ether, tert.butyl methyl ether, tetrahydrofuran and dioxane; esters, such as ethyl and propyl acetate and n-butyl acetate; glycol ether acetates, such as methyl, ethyl and butyl glycol acetate, ketones, such as acetone and cyclohexanone; dialkyl carboxylic acid amides, such as dimethyl formamide, dimethyl acetamide and N-methyl pyrrolidone; aromatic hydrocarbons, such as benzene, toluene and the xylenes; aliphatic hydrocarbons, such as hexane and isooctane; alicyclic hydrocarbons, such as cyclohexane; and chlorinated hydrocarbons, such as methylene chloride, chloroform, dichloroethane and tert.butyl chloride.
However, the modifying reagent may also be used as the solvent. For example, alcohols, such as methanol, ethanol or isopropanol, and amines, such as butylamine, etc., may be used.
A plasticizer may also be used as the solvent in the modification reaction.
The physical and chemical properties of the polymers according to the invention initially formed may be significantly varied by this polymer-analog reaction. Thus, a soft resin with extremely tacky properties is obtained after treatment with methanol. The precipitation of polymers with solvents having a lower or higher polarity than the reaction medium leads to non-tacky elastic polymers which can be drawn to form transparent films.
The polymers according to the invention may be used for coating, bonding, sealing, filling and as a material, for example as hotmelt adhesives, tackifiers or high-tack dispersions. The polymers according to the invention in the form of their salts are also suitable as builders for detergents, as stabilizers for emulsions and as thickeners.
The polymers or modified polymers according to the invention may be used in bulk, in solution or in emulsion/dispersion. By virtue of their variable properties, they may be used as binders, adhesives, adhesive sealing compounds and coatings. They are particularly suitable for substrates varying in their elastic behavior or in their thermal expansion coefficient, as is generally the case with different substrates. Suitable substrates are metals, such as aluminium, wood, paperboard, paper, wall coverings, such as wallpaper, cork, leather, felt, textiles, plastics (particularly floor coverings of PVC, linoleum and polyolefins), mineral substrates, such as glass, quartz, slags, rock and ceramics and metals. The plastics may be present in the form of films, sheets or other molded products.
The polymers or modified polymers according to the invention are particularly suitable for the production of printing ink binders, adhesive sticks, floor covering adhesives, multipurpose adhesives, plastisols, hotmelt adhesives or hotmelt sealants and paste-form sealants, such as jointing compounds. They may also be used for coating hard surfaces, textiles and paper.
The polymers or modified polymers according to the invention are extrudable and are therefore suitable for injection molding. They may be used, for example, as materials.
The polymers or modified polymers according to the invention, more particularly the salts and reaction products with polyethylene glycols, are suitable as polymeric emulsifiers, dispersants, thickeners or builders for detergents.
The low molecular weight polymers or modified polymers are suitable as soft resins and as tackifiers for modifying other commercially available polymers and polymer dispersions.
The invention is illustrated by the following Examples.